It isn't green and it doesn't glow

For some time I have been aware of a common misconception about radio telescopes. Some people think that they are like mobile phone masts and electricity pylons; they think that they are emitting some kind of radiation. These people then link the word radiation with green, glowing things and get a bit worried about possible damage to their health.This has recently been a concern of people living near a proposed site for the SKA in western Australia. However, a radio telescope doesn't emit (give out) radiation; it quietly sits there 'listening' to the radiation that would be there anyway, radio telescope or not.

Unfortunately, the stigma attached to the word radiation is widespread, and the difference in understanding of the term between scientists and non-scientists can cause problems (as in concerns over the SKA show). Scientists tend to use the word radiation quite freely to describe the thing that non-scientists know of as light. Yes, I do mean the same stuff that comes out of a light bulb. Compare 'optical radiation emitter' with 'torch' and you will notice that the first sounds much scarier than the second, even though they are both the same thing. When scientists use the word radiation, they are using it to cover the whole of the electromagnetic spectrum; everything from radio waves to the colours of the rainbow and X-rays. Not all radiation is bad for us.

Having said all that about radiation, the point remains that radio telescopes do not emit radiation any more than a herd of cows does.

Posted in astro blog by Stuart on Saturday 14th May 2005 (23:21 UTC) | Permalink
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